The present invention relates to a new series of imidazole derivatives with anti-inflammatory activity, as well as to a process for their preparation, to the pharmaceutical compositions containing them and to their use in medicine.
In many acute as well as chronic inflammatory processes, substances derived from the metabolism of arachidonic acid are involved. These substances form a large family of compounds of lipidic nature that are the result of the action of a series of enzymes which form what is called the arachidonic acid cascade. The most important one from the therapeutic point of view is prostaglandin G/H synthase (PGHS), also known as cyclooxygenase (COX), which catalyzes the formation of vasoactive and inflammatory substances such as prostaglandins (PGE2, PGD2, PGF2), prostacyclin (PGI2) and thromboxane A2 (TXA2).
Inhibition of cyclooxygenase (COX) is the mechanism of action responsible for the effect of most anti-inflammatory drugs on the market (non-steroidal anti-inflammatory drugs, NSAIDs). Said inhibition also reduces the levels of prostaglandins at gastric level, which, in view of the protective role of said molecules on the gastric mucosa, has been correlated to the well known gastric effects of NSAIDs.
In the early 90""s two cyclooxygenase isoforms, COX-1 and COX-2, were described. COX-1 is the constitutive isoform, present in many tissues, but preferentially in the stomach, kidney and platelets. Its inhibition is responsible for the gastric and renal effects of NSAIDs. On the other hand, COX-2 is an inducible isoform, which is expressed as a consequence of an inflammatory or mitogenic stimulus in a wide range of tissues such as macrophages, chondrocytes, fibroblasts and endothelial cells.
The discovery of the inducible isoenzyme of PGHS (PGHS2 or COX-2) has allowed the synthesis of selective COX-2 inhibitors which presumably improve the gastric tolerance of these drugs, since as they inhibit the constitutive form present in the stomach to a lesser extent, they exhibit reduced ulcerogenic potency (one of the most characteristic side effects of non-selective inhibitors). The present invention describes new cyclooxygenase inhibitors with selectivity for the isoform 2 (COX-2).
The present invention relates to the new compounds of general formula I 
wherein R1, R2, R3 and R4 represent the specific combinations of values defined in the following table:
The present invention also relates to the addition salts of the compounds of the invention as well as to their solvates and prodrugs. The term prodrug refers to any precursor of a compound of formula I which is able to be transformed in vivo into a compound of formula I.
The present invention also relates to the pharmaceutical compositions which comprise an effective amount of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof and one or more pharmaceutically acceptable excipients.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the manufacture of a medicament for the treatment or prevention of diseases mediated by cyclooxygenase, specially cyclooxygenase-2.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the manufacture of a medicament for the treatment of inflammation, pain and/or fever.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the manufacture of a medicament for inhibiting prostanoid-induced smooth muscle contraction.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the manufacture of a medicament for the treatment or prevention of dysmenorrhea, preterm labour, asthma and bronchitis.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the manufacture of a medicament for the treatment or prevention of familial adenomatous polyposis.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the manufacture of a medicament for the treatment or prevention of cancer, preferably gastrointestinal cancers, and more preferably colon cancer.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the manufacture of a medicament for the treatment or prevention of cerebral infarction, epilepsy, and neurodegenerative diseases such as Alzheimer""s disease and dementia.
The present invention also relates to a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of diseases mediated by cyclooxygenase, specially cyclooxygenase-2.
The present invention also relates to a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment of inflammation, pain and/or fever.
The present invention also relates to a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for inhibiting prostanoid-induced smooth muscle contraction.
The present invention also relates to a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of dysmenorrhea, preterm labour, asthma and bronchitis.
The present invention also relates to a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of familial adenomatous polyposis.
The present invention also relates to a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of cancer, preferably gastrointestinal cancers, and more preferably colon cancer.
The present invention also relates to a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of cerebral infarction, epilepsy, and neurodegenerative diseases such as Alzheimer""s disease and dementia.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of diseases mediated by cyclooxygenase, specially cyclooxygenase-2.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment of inflammation, pain and/or fever.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for inhibiting prostanoid-induced smooth muscle contraction.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of dysmenorrhea, preterm labour, asthma and bronchitis.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of familial adenomatous polyposis.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of cancer, preferably gastrointestinal cancers, and more preferably colon cancer.
The present invention also relates to the use of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof for the treatment or prevention of cerebral infarction, epilepsy, and neurodegenerative diseases such as Alzheimer""s disease and dementia.
The present invention also relates to a method of treating or preventing diseases mediated by cyclooxygenase, specially cyclooxygenase-2, in a mammal in need thereof, specially a human being, which comprises administering to said mammal a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof.
The present invention also relates to a method of treating inflammation, pain and/or fever in a mammal in need thereof, specially a human being, which comprises administering to said mammal a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof.
The present invention also relates to a method of inhibiting prostanoid-induced smooth muscle contraction in a mammal in need thereof, specially a human being, which comprises administering to said mammal a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof.
The present invention also relates to a method of treating or preventing dysmenorrhea, preterm labour, asthma and bronchitis in a mammal in need thereof, specially a human being, which comprises administering to said mammal a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof.
The present invention also relates to a method of treating or preventing familial adenomatous polyposis in a mammal in need thereof, specially a human being, which comprises administering to said mammal a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof.
The present invention also relates to a method of treating or preventing cancer, preferably gastrointestinal cancers, and more preferably colon cancer, in a mammal in need thereof, specially a human being, which comprises administering to said mammal a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof.
The present invention also relates to a method of treating or preventing cerebral infarction, epilepsy, and neurodegenerative diseases such as Alzheimer""s disease and dementia in a mammal in need thereof, specially a human being, which comprises administering to said mammal a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt, solvate or prodrug thereof.
Another object of the present invention is to provide a process for preparing the compounds of formula I, which comprises:
a) reacting a compound of formula II 
wherein R1, R2, R3 and R4 have the meaning described above, with a chlorinating agent; or
b) when in a compound of formula I R1 represents xe2x80x94CH3, reacting a compound of formula VI 
wherein R2, R3 and R4 have the meaning described above, with an oxidizing agent; or
c) when in a compound of formula I R1 represents xe2x80x94NH2, reacting a compound of formula VII 
wherein R2, R3 and R4 have the meaning described above, with hydroxylamine-O-sulfonic acid; or
d) if desired, after the above steps, reacting a compound of formula I with an acid or a base to give the corresponding salt.
In a preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(4-isopropoxyphenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(4-fluoro-3-methoxyphenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(4-ethoxy-3-fluorophenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(3,5-difluorophenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(3-chloro-4-methoxyphenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(3-chloro-4-ethoxyphenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-[3,4-(methylenedioxy)phenyl]-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(3,5-dichloro-4-methoxyphenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(4-isopropylphenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-5-(4-N,N-diethylaminophenyl)-1-(4-methylsulfonylphenyl)imidazole or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-[4-chloro-5-(4-fluoro-3-methoxyphenyl)imidazol-1-yl]benzenesulfonamide or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-[4-chloro-5-(4-ethoxy-3-fluorophenyl)imidazol-1-yl]benzenesulfonamide or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-[4-chloro-5-(3-chloro-4-ethoxyphenyl)imidazol-1-yl]benzenesulfonamide or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-[4-chloro-5-(3-chloro-4-methoxyphenyl)imidazol-1-yl]benzenesulfonamide or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-[4-chloro-5-(3,5-dichloro-4-methoxyphenyl)imidazol-1-yl]benzenesulfonamide or a salt, solvate or prodrug thereof.
In another preferred embodiment of the invention, the compound of formula I is 4-chloro-1-(4-methylsulfonylphenyl)-5-(4-propylphenyl)imidazole or a salt, solvate or prodrug thereof.
The compounds of the present invention contain one or more basic nitrogens and, consequently, they can form salts with organic as well as inorganic acids, which are also included in the present invention. Examples of said salts include salts with inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, perchloric acid, sulfuric acid or phosphoric acid; and salts with organic acids, such as methanesulfonic acid, trifluoromethanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, fumaric acid, oxalic acid, acetic acid or maleic acid, among others. The compounds of formula I where R1=NH2 can also form salts with bases, which are also included in the present invention; examples thereof include salts with inorganic cations such as sodium, potassium, calcium, magnesium, lithium, aluminum, zinc, etc. There is no limitation on the nature of said salts, provided that, when used for therapeutic purposes they are pharmaceutically acceptable. The salts can be prepared by treatment of a compound of formula I with a sufficient amount of the desired acid or base to give the salt in a conventional manner. The compounds of formula I and their salts differ in certain physical properties, such as solubility, but they are equivalent for the purposes of the invention.
Some compounds of the present invention may exist in solvated form, including hydrated forms. In general, the solvated forms, with pharmaceutically acceptable solvents such as water, ethanol and the like, are equivalent to the unsolvated form for the purposes of the invention.
The present invention also provides a process for the preparation of the compounds of formula I. As it will be obvious to a person skilled in the art, the precise method used for the preparation of a given compound can vary depending on its chemical structure. Furthermore, in some of the processes that are detailed below it may be necessary or appropriate to protect the reactive or labile groups using conventional protecting groups. Both the nature of said protecting groups and the processes for their introduction and removal are well known and belong to the state of the art (see for example Greene T. W., xe2x80x9cProtective Groups in Organic Synthesisxe2x80x9d, John Wiley and Sons, New York, 1981).
The compounds of formula I are in general obtained by reacting a compound of formula II with a suitable chlorinating agent such as N-chlorosuccinimide, as shown in the following scheme: 
wherein R1, R2, R3 and R4 have the meaning described above. This reaction is carried out in a suitable solvent such as acetonitrile, and heating, preferably at reflux.
The compounds of formula II can in general be obtained by reacting an imine of formula III 
with an isocyanide of formula Lxe2x80x94CH2xe2x80x94NC (wherein L is a good leaving group) such as tosylmethylisocyanide or 1H-benzotriazol-1-ylmethylisocyanide, in the presence of a base such as K2CO3, in a suitable solvent such as methanol-dimethoxyethane mixtures, and heating, preferably at reflux.
The imines of formula III can be prepared by condensation of an aldehyde of formula IV 
wherein R2, R3 and R4 have the meaning described above, with an amine of formula R1SO2xe2x80x94C6H4xe2x80x94NH2 (V), and heating at reflux in a suitable solvent such as toluene, in a Dean Stark. The compounds of formula IV and V are commercially available or can be prepared according to procedures well known by those skilled in the art, such as for example those described in the examples.
Alternatively, a compound of formula I or II wherein R1 represents a group xe2x80x94CH3 and R2, R3 and R4 have the meaning described above, can also be prepared from the corresponding thioether of formula VI or VIxe2x80x2, respectively 
wherein R2, R3 and R4 have the meaning described above, by oxidation with a suitable oxidizing agent such as m-chloroperbenzoic acid, magnesium monoperoxyphtalate or Oxone(copyright), in a suitable solvent such as a halogenated hydrocarbon, for example dichloromethane.
Alternatively, the compounds of formula I wherein R1 represents a group xe2x80x94NH2 can also be prepared from the corresponding sodium sulfinate of formula VII 
wherein R2, R3 and R4 have the meaning described above, by reaction with hydroxylamine-O-sulfonic acid in a suitable solvent such as water or water/tetrahydrofuran mixtures.
The compounds of formula VII are prepared from the methylsulfoxide of formula VIII, 
wherein R2, R3 and R4 have the meaning described above, by a process that involves treatment with acetic anhydride to give the corresponding acetoxymethylthio derivative (xe2x80x94SCH2OAc), followed by chlorination of the position 4 of the imidazole ring using the general procedure described above for the preparation of the compounds of formula I and finally oxidation of the group xe2x80x94SCH2OAc with a suitable oxidizing agent such as magnesium monoperoxyphtalate to give the xe2x80x94SO2CH2OAc derivative, which is transformed into a sodium sulfinate of formula VII by treatment with a base, for example sodium hydroxide.
The compounds of formula VIII and VIxe2x80x2 can be prepared using the same general method described above for preparing the compounds of formula II but starting from compounds of formula III which contain a group xe2x80x94SOCH3 or xe2x80x94SCH3, respectively, instead of xe2x80x94SO2CH3. The compounds of formula VI can be prepared from the corresponding compound VIxe2x80x2 by chlorination, according to the method previously described. The derivatives VIII can also be prepared from a compound of formula VIxe2x80x2, by oxidation with a suitable oxidizing agent.
The salts of the compounds of formula I can be prepared by conventional methods by treatment for example with an acid such as hydrochloric acid, sulfuric acid, nitric acid, oxalic acid or methanesulfonic acid or with a base such as sodium or potassium hydroxide.
As mentioned above, the compounds of the present invention act by inhibiting the cyclooxygenase-2 enzyme (COX-2). Therefore, they are useful for the treatment or prevention of inflammation, pain and/or fever associated with a wide range of diseases or pathologies, which include among others: rheumatic fever; symptoms associated with influenza or other viral infections; common cold; low back and neck pain; dysmenorrhea; headache; toothache; myositis; neuralgia; synovitis; bursitis; arthritis, including rheumatoid arthritis and juvenile arthritis; degenerative joint diseases, including osteoarthritis; gout and ankylosing spondylitis; lupus erythematosus; tendinitis; sprains, strains and other similar injuries, such as those produced during sport performance; pain following surgical or dental procedures; and pain associated with cancer. They are also useful in the treatment of skin inflammatory diseases, including psoriasis, eczema, burns and dermatitis.
The compounds of the present invention can also be useful for the treatment of other pathologies mediated by COX-2. For example, the compounds of formula I can inhibit cell proliferation and consequently they can be useful for the treatment or prevention of familial adenomatous polyposis and cancer, specially those cancers that produce prostaglandins or that express cyclooxygenase. The compounds of the invention are useful for the treatment, for example, of liver, bladder, pancreas, ovary, prostate, cervix, lung, breast and skin cancer, and specially gastrointestinal cancers such as colon cancer.
The compounds of the present invention can also inhibit prostanoid-induced smooth muscle contraction and thus can be useful for the treatment of dysmenorrhea, preterm labour, asthma and bronchitis. Other uses of the compounds of formula I include the treatment or prevention of cerebral infarction, epilepsy, and neurodegenerative diseases, such as Alzheimer""s disease and dementia.
Likewise, the compounds of the present invention can be used for treating inflammation in diseases such as vascular diseases, migraine, periarteritis nodosa, thyroiditis, aplastic anaemia, Hodgkin""s disease, scleroderma, type I diabetes, myasthenia gravis, sarcoidosis, nephrotic syndrome, Behcet""s syndrome, polymyositis, hypersensitivity, conjunctivitis, gingivitis and myocardial ischaemia.
Due to their selectivity for cyclooxygenase-2, the compounds of the present invention are useful as an alternative to non-steroidal anti-inflammatory drugs (NSAIDs), specially in those cases in which NSAIDs may be contra-indicated.
According to the activity of the products herein described, the present invention also relates to compositions which comprise a compound of the present invention, together with an excipient or other auxiliary agents if necessary. The compounds of the present invention can be administered as any pharmaceutical formulation, the nature of which will depend, as it is well known, upon the route of administration and upon the nature of the pathology to be treated.
According to the present invention, solid compositions for oral administration include tablets, powders for extemporaneous suspensions, granulates and capsules. In tablets, the active component is admixed with at least one inert diluent such as lactose, starch, mannitol, microcrystalline cellulose or calcium phosphate; with a binding agent such as for example starch, gelatin, microcrystalline cellulose or polyvinylpyrrolidone; and with a lubricating agent, such as for example magnesium stearate, stearic acid or talc. The tablets can be coated by known techniques with the purpose of delaying their disintegration and absorption in the gastrointestinal tract, and thereby provide a sustained action over a longer period. Gastric or enteric coatings can be made with sugar, gelatin, hydroxypropylcellulose, acrylic resins, etc. Sustained-release tablets might also be obtained using an excipient which produces regressive osmosis, such as galacturonic acid polymers. Preparations for oral use can also be presented as hard capsules of absorbable material, such as for example gelatin, wherein the active compound is mixed with an inert solid diluent and lubricating agents, or pasty materials, such as ethoxylated saturated glycerides, which might also provide controlled release. Soft gelatin capsules are also possible, wherein the active compound is mixed with water or an oily medium, for example coconut oil, liquid paraffin, or olive oil.
Powders and granulates for the preparation of suspensions by the addition of water can be obtained by mixing the active compound with dispersing or wetting agents; suspending agents, such as sodium carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, sodium alginate, polyvinylpyrrolidine, gum tragacanth, xantham gum, gum acacia, and one or more preservatives, such as methyl or propyl p-hydroxybenzoate. Other excipients can also be added, for example sweetening, flavouring and colouring agents.
Liquid forms for oral administration include emulsions, solutions, suspensions, syrups and elixirs containing commonly used inert diluents, such as distilled water, ethanol, sorbitol, glycerol or propylene glycols. Said compositions can also contain coadjuvants such as wetting, suspending, sweetening, flavouring, preserving agents and buffers.
Injectable preparations, according to the present invention, for parenteral administration comprise sterile aqueous or non-aqueous solutions, suspensions or emulsions, in a suitable non-toxic solvent or diluent. Examples of aqueous solvents or suspending media are distilled water for injection, Ringer""s solution and isotonic sodium chloride solution. As non-aqueous solvents or suspending media propylene glycol, polyethylene glycol, vegetable oils such as olive oil, or alcohols such as ethanol can be used. These compositions can also contain coadjuvants, such as wetting, preserving, emulsifying and dispersing agents. They may be sterilized by any known method or prepared as sterile solid compositions which will be dissolved in water or any other sterile injectable medium immediately before use. It is also possible to start from sterile materials and keep them under these conditions throughout all the manufacturing process.
The dosage and frequency of doses will depend upon the nature and severity of the disease to be treated, the age and body weight of the patient, as well as the route of administration. In general, the daily dose for an adult will be comprised between 1 and 1000 mg per day, which can be administered as a single or divided doses. However, in special cases, doses outside these margins might be necessary. A person skilled in the art will be able to easily determine the suitable dose for each situation.
Some examples of representative formulations for tablets, capsules and injectable preparations are cited below. They can be prepared by conventional procedures and are useful for inhibiting cyclooxygenase-2.
The activity of the compounds of the present invention can be determined using the following test:
Inhibition of Cyclooxygenase-1 (COX-1) and Cyclooxygenase-2 (COX-2) Activity in Human Cell Lines
The inhibition of COX-1 and COX-2 is determined by assessing the PGE2 production after stimulation with arachidonic acid in cell lines expressing human COX-1 (U-937 from human histiocitic lymphoma) and human COX-2 (143.98.2 from human osteosarcoma), respectively.
The osteosarcoma-derived cells were cultured in 1 mL of DMEM culture medium supplemented with 10% fetal calf serum, in 24-well multidishes until confluence. U-937 cells were cultured in RPMI medium supplemented with 10% fetal calf serum in flasks.
To evaluate COX-2 activity, the medium was removed and replaced with Hepes-buffered saline solution (HBSS) without Ca2+/Mg2+ (2xc3x97105 cells/well). To evaluate COX-1 activity, the medium was removed and U-937 cells were resuspended to a final density of 3xc3x97106 cells/mL in HBSS without Ca2+/Mg2+ (1 mL/well, in 24-well multidishes). 1 xcexcL of a solution of the test compound dissolved in DMSO or vehicle was added, and the samples were incubated for 15 min at 37xc2x0 C. (5% CO2 and 95% humidity). Arachidonic acid was added (final concentration: 10 xcexcM) and the samples were incubated for 10 min more. Next the reactions were quenched by adding indomethacin (8 mM, 30 xcexcL). The amount of PGE2 in the supernatant was determined by specific enzymatic immunoassay (Kit Prostaglandin E2, Biotrak EIA system RPN222, Amersham Pharmacia Biotech). All the assays were performed in triplicate.
The results obtained with the compounds of the present invention are shown in the following table, where the % of inhibition of COX-1 and COX-2 activity at a concentration of 0.1 xcexcM of test compound are reported.
The results of the table above show that the compounds of formula I are potent and selective COX-2 inhibitors.
The following examples illustrate, but do not limit, the scope of the present invention. The following abbreviations have been used in the examples:
EtOAc: ethyl acetate
Ac2O: acetic anhydride
NaOAc: sodium acetate
DME: dimethoxyethane
DMF: dimethylformamide
DMSO: dimethylsulfoxide
EtOH: ethanol
Et2O: diethyl ether
MeOH: methanol
Et3N: triethylamine
THF: tetrahydrofuran
TMS: tetramethylsilane
67 mg of Na2WO4, 8 drops of acetic acid and 19 mL of H2O were introduced into a flask and heated to 65xc2x0 C. Then, 19 mL (153 mmol) of 4-methylthioaniline was added followed by the dropwise addition of 34.5 mL (337 mmol) of H2O2. The mixture was stirred at 65xc2x0 C. for 1.5 h and, after cooling, 800 mL of 1N HC and 500 mL of CHCl3 was added. The layers were separated and the aqueous phase was washed with more CHCl3. The aqueous phase was then basified with 25% NaOH and extracted with CHCl3. The organic phase was washed with brine and dried over MgSO4. The solvent was removed, yielding 19.80 g of the product as a white solid (75% yield).
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 2.97 (s, 3 H), 4.04 (s, 2 H), 6.66 (d, J=9 Hz, 2 H), 7.56 (d, J=9 Hz, 2 H).
20 g (143.66 mmol) of 4-methylthioaniline was placed in a flask and dissolved in 660 mL of CH2Cl2. The solution was cooled to 0xc2x0 C. and 35.42 g (143.66 mmol) of m-chloroperbenzoic acid was added. The mixture was stirred for 3 h at room temperature and poured into CHCl3. It was then washed with saturated NaHCO3 solution, dried over MgSO4 and the solvent was removed, yielding a crude product that was purified by chromatography on silica gel, using MeOH/EtOAc/hexane mixtures of increasing polarity as eluent. The title compound of the example was obtained as a white solid (17.84 g, 80%).
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 2.68 (s, 3 H), 4.02 (s, 2 H), 6.75 (d, J=8.7 Hz, 2 H), 7.45 (d, J=8.7 Hz, 2 H).
To a solution of 2 g (16.38 mmol) of 4-hydroxybenzaldehyde in 100 mL of DMF, 2.72 g (19.69 mmol) of K2CO3, 2.74 g (16.52 mmol) of KI and 3.94 mL (39.38 mmol) of 2-iodopropane was added under argon. The mixture was stirred at 80xc2x0 C. overnight, concentrated and the residue obtained was partitioned between CHCl3 and H2O. The phases were separated, the aqueous phase was extracted with CHCl3 and the combined organic phases were dried over MgSO4 and concentrated. The crude product obtained was purified by chromatography on silica gel using EtOAc/hexane mixtures of increasing polarity as eluent, to give 2.08 g of the title compound of the example as an oil (77% yield).
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 1.39 (d, J=6 Hz, 6 H), 4.67 (m, 1 H), 6.96 (d, J=8.7 Hz, 2 H), 7.81 (d, J=8.7 Hz, 2 H), 9.87 (s, 1 H).
Following a similar procedure to that described in reference example 3, but starting from 3-chloro-4-hydroxybenzaldehyde instead of 4-hydroxybenzaldehyde and using methyl iodide instead of 2-iodopropane, the title compound of the example was obtained as an oil (97% yield).
1H-NMR (300 MHz, CD3OD xcex4 TMS): 3.98 (s, 3 H), 7.04 (d, J=8.4 Hz, 1 H), 7.77 (d, J=8.4 Hz, 1 H), 7.89 (s, 1 H), 9.84 (s, 1 H).
Following a similar procedure to that described in reference example 3, but starting from 3-chloro-4-hydroxybenzaldehyde instead of 4-hydroxybenzaldehyde and using ethyl iodide instead of 2-iodopropane, the title compound of the example was obtained as an oil (98% yield).
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 1.52 (t, J=6.9 Hz, 3 H), 4.21 (q, J=6.9 Hz, 2 H), 7.02 (d, J=8.7 Hz, 1H), 7.76 (d, J=8.7 Hz, 1 H), 7.91 (s, 1 H), 9.85 (s, 1 H.
Following a similar procedure to that described in reference example 3, but starting from 3-fluoro-4-hydroxybenzaldehyde instead of 4-hydroxybenzaldehyde and using ethyl iodide instead of 2-iodopropane, the title compound of the example was obtained as an oil (48% yield).
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 1.51 (t, J=7.2 Hz, 3 H), 4.21 (q, J=7.2 Hz, 2 H), 7.06 (t, J=7.8 Hz, 1 H), 7.62 (m, 2 H), 9.86 (s, 1 H).
a) Ethyl 3,4-(methylenedioxy)benzoate
A mixture of 3 g (18 mmol) of piperonylic acid and 9 mL of SOCl2 was heated at reflux under argon for 1 h. The solvent was removed and the residue was stirred with a mixture of 5 mL of Et3N and 75 mL of ethanol for 1.5 h at room temperature. The solvent was removed and the residue was partitioned between CH2Cl2 and H2O. The layers were separated and the aqueous phase was extracted with CH2Cl2. The combined organic phases were dried over MgSO4 and concentrated, affording 2.54 g of a crude product that was directly used in the following step.
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 1.36 (t, J=7.2 Hz, 3 H), 4.33 (q, J=7.2 Hz, 2 H), 6.01 (s, 2H), 6.82 (d, J=8.1 Hz, 1 H), 7.46 (s, 1 H), 7.64 (d, J=8.1 Hz, 1 H).
b) 3,4-(Methylenedioxy)phenylmethanol
To a mixture of 0.99 g (26.16 mmol) of LiAlH4 and 80 mL of Et2O, 2.54 g (13.08 mmol) of ethyl 3,4-(methylenedioxy)benzoate (obtained in the preceding section) dissolved in 160 mL of Et2O was added under argon, and the mixture was stirred overnight at room temperature. A mixture of 1.62 mL of H2O and 3.41 mL of THF, followed by 1.62 mL of 15% NaOH and then 4.43 mL of H2O were added dropwise. The resulting mixture was filtered, washed with Et2O and EtOAc, and the solvent was evaporated. The residue was partitioned between H2O and EtOAc, the layers were separated, the aqueous phase was extracted with EtOAc and the combined organic phases were dried over MgSO4 and concentrated, yielding 1.88 g of the desired product (94% yield).
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 1.81 (s, 1 H), 4.57 (s, 2 H), 5.96 (s, 2 H), 6.80 (m, 2 H), 6.87 (s, 1 H).
c) Title Compound
To a mixture of 1.18 mL (13.50 mmol) of oxalyl chloride and 17.2 mL of CH2Cl2, cooled to xe2x88x9278xc2x0 C., a mixture of 2.1 mL of DMSO and 3.9 mL of CH2Cl2 was added dropwise and under argon, and the resulting mixture was stirred for 5 min. Next, 1.88 g (12.36 mmol) of 3,4-(methylenedioxy)phenylmethanol (obtained in the preceding section) dissolved in a mixture of 1.6 mL of DMSO and 1.6 mL of CH2Cl2 was added dropwise and the mixture was stirred for 30 min at xe2x88x9278xc2x0 C. Then, 14.7 mL (106 mmol) of Et3N was added, the mixture was stirred for 10 min at the same temperature and was then allowed to warm up to room temperature. It was poured into a mixture of ice and H2O, extracted with CH2Cl2 and the combined organic phases were dried over MgSO4 and concentrated, yielding 1.6 g of the title compound of the example as an oil (86% yield).
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 6.08 (s, 2 H), 6.93 (d, J=7.8 Hz, 1 H), 7.34 (s, 1 H), 7.42 (d, J=7.8 Hz, 1 H), 9.81 (s, 1 H).
a) 2,6-Dichloro-4-hydroxymethylphenol
Following a similar procedure to that described in section b of reference example 7, but starting from ethyl 3,5-dichloro-4-hydroxybenzoate instead of ethyl 3,4-(methylenedioxy)benzoate, the desired compound was obtained in a 67% yield.
1H-NMR (300 MHz, CDCl3+CD3OD xcex4 TMS): 3.86 (s, 2 H), 4.54 (s, 2 H), 7.27 (s, 2 H).
b) 3,5-Dichloro-4-methoxyphenylmethanol
Following a similar procedure to that described in reference example 3, but starting from 2,6-dichloro-4-hydroxymethylphenol (obtained in the preceding section) instead of 4-hydroxybenzaldehyde and using methyl iodide instead of 2-iodopropane, the desired compound was obtained in a 77% yield.
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 2.7 (s, broad signal, 1 H), 3.86 (s, 3 H), 4.57 (s, 2 H), 7.26 (s, 2 H).
c) Title Compound
Following a similar procedure to that described in section c of reference example 7, but using 3,5-dichloro-4-methoxyphenylmethanol (obtained in the preceding section) instead of 3,4-(methylenedioxy)phenylmethanol, the title compound of the example was obtained as an oil (94% yield).
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 3.99 (s, 3 H), 7.82 (s, 2 H), 9.86 (s, 1 H).
Following a similar procedure to that described in reference example 7, but starting from 4-propylbenzoic acid instead of piperonylic acid, the title compound of the example was obtained as an oil.
1H-NMR (300 MHz, CDCl3 xcex4 TMS): 0.98 (t, J=7 Hz, 3 H), 1.68 (m, 2 H), 2.67 (t, J=7 Hz, 2 H), 7.34 (d, J=8.4 Hz, 2 H), 7.80 (d, J=8.4 Hz, 2 H), 9.98 (s, 1 H).